No. 1, November, 1921] PATHOLOGY 35 



192. DooLiTTLE, S. P. Influence of temperature on the development of mosaic diseases. 



[Abstract.] Phytopathology 11: 4G-47. 1921. 



193. DooLiTTLE, S. P. The relation of wild host plants to the overwintering of cucurbit 

 mosaic. [Abstract.] Phytopathology 11: 47. 1921. 



194. Fromme, F. D., and S. A. Wingard. Varietal susceptibility of beans to rust. Jour. 

 Agric. Res. 21: 385—104. 5 pi. 1921. — The relative susceptibility of 64 varieties of garden 

 and field beans to rust (Uromyces appendiculatus) has been determined, taking the suscep- 

 tibility of the variety Tennessee Green Pod as a standard. Variation from the standard in 

 reduction in number of infections, reduction of size of uredinium, abortion of infection, im- 

 mediate production of telia instead of uredinia, and lengthening of the period of infection, 

 has been considered. With the exception of a few varieties, little or no variation occurred in 

 the susceptibility of individuals in the majority of varieties studied. Correlation between 

 rust-resistance and various plant and seed characters were observed. As a class, bush beans 

 are more resistant than pole beans, and varieties with wax pods more resistant than those 

 with green pods. Varieties having red (mottled or self-colored seeds) are resistant. White- 

 seeded types, as a class, are more susceptible than colored-seeded types. Varieties having 

 the "marrow" type of seeds are resistant, while those of the "pea" type are most susceptible. 

 Experiments with dry-shell beans show that the rust, under certain conditions, may reduce 

 the yield of seeds 50 per cent or more. Two biological strains of the rust fungus are 

 described. — W. H. Burkholder. 



195. Frost, John F., and G. N. Hoffer. Kernel starchiness as an index of susceptibility 

 to root, stalk, and ear-rots of corn. [Abstract.] Phytopathology 11: 33-34. 1921. 



196. McClintock, J. A. Overwintering of mosaic of annuals. [Abstract.] Phytopa- 

 thology 11: 47. 1921. 



197. Nelson, Ray. Tissue breakdown in fruits and vegetables. [Abstract.] Phytopa- 

 thology 11: 44. 1921. 



198. Weiss, Freeman, and C. R. Orton. Second report of the reaction of American 

 potato varieties to the wart disease. [Abstract.] Phytopathology 11: 57. 1921. 



THE PATHOGENE (BIOLOGY, INFECTION PHENOMENA, DISPERSAL) 



199. Fawcett, H. S. Some relations of temperatute to growth and infection in the citrus 

 scab fungus, Cladosporium citri. Jour. Agric. Res. 21 : 243-253. 1921. — Tests were made under 

 controlled conditions to determine thermal relations. Sour orange (Citrus aurantium) seed- 

 lings in actively growing condition were used. The conditions for infection are, viable spores 

 of Cladosporium, young leaves of a susceptible species, moisture, and temperatures between 

 16 and 23°C. Detached leaves are infected at temperatures from 16 to 27.5°C.; the optimum 

 temperature is from 16 to 27.5°C. The optimum temperature for growth of C. citri is 21°C., 

 with 27.5 the maximum in water and 32 on corn-meal agar. The incubation period is shortest 

 with plants held at 21°C. — Cladosporium citri is atypical for the genus. At certain tempera- 

 tures the spores are ejected with considerable force from the ends of the hyphae. — D. Reddick. 



200. Jackson, H. S., and E. B. Mains. The aecidium of the orange rust of wheat, 

 Puccinia triticina. [Abstract.] Phytopathology 11: 40. 1921. 



201. McFarland, Frank T. Infection experiments with Claviceps. [Abstract.] Phyto- 

 pathology 11: 41-42. 1921. 



202. Monteith, John, Jr. Seed transmission and overwintering of cabbage black rot. 

 [Abstract.] Phytopathology 11: 53-54. 1921. 



